Games like Alchemage
Games like Alchemage include Terraria, Starbound, Forager, Don't Starve Together, and Necesse. We matched them by the tags players give Alchemage on Steam (Adventure, Indie, Action, Casual, and Sandbox): closest matches first, and among equally close ones the better-known games.

Terraria
Shared: Sandbox · Adventure · 2D

Starbound
Shared: Adventure · Sandbox · Survival

Forager
Shared: Indie · Pixel Graphics · Adventure

Don't Starve Together
Shared: Adventure · Survival · Multiplayer

Necesse
Shared: Pixel Graphics · Adventure · Sandbox

Rust
Shared: Survival · Adventure · Multiplayer

Wobbly Life
Shared: Adventure · Sandbox · Multiplayer

Broforce
Shared: Action · Pixel Graphics · 2D

Don't Starve
Shared: Adventure · Indie · Survival

Orion Sandbox Enhanced
Shared: Adventure · Action · Indie

Timberman
Shared: Indie · Casual · Action

Pikuniku
Shared: Adventure · Indie · Casual

PixARK
Shared: Adventure · Survival · Sandbox

ARK: Survival Ascended
Shared: Adventure · Survival · Multiplayer

Palworld
Shared: Indie · Survival · Adventure

Tinkerlands
Shared: Sandbox · Indie · Pixel Graphics

Stardew Valley
Shared: Pixel Graphics · Multiplayer · Sandbox

The Escapists
Shared: Pixel Graphics · Indie · 2D

Noita
Shared: Indie · Pixel Graphics · Sandbox

Human Fall Flat
Shared: Adventure · Sandbox · Multiplayer

The Final Station
Shared: Indie · Adventure · Pixel Graphics

Core Keeper
Shared: Survival · Sandbox · Pixel Graphics

ARK: Survival Evolved
Shared: Adventure · Survival · Multiplayer

Skul: The Hero Slayer
Shared: Indie · Action · Pixel Graphics